Process optimization of plasma-catalytic formaldehyde removal using MnOx-Fe2O3 catalysts by response surface methodology

To remove the toxic formaldehyde efficiently, a non-thermal plasma (NTP) system incorporated with MnOx-Fe2O3 catalyst has been developed herein. A response surface methodology (RSM) was utilized to explore the effects of a variety of experimental parameters (gas flow rate, molar ratio of Fe/Mn, and discharge power) on formaldehyde degradation systematically. The results demonstrated that the discharge power has the greatest impact on the formaldehyde degradation process, while the molar ratio of Fe/Mn has the least influence. Moreover, the amount of adsorbed oxygen species, reducibility, and average specific surface area of the tested catalyst are estimated as the dominant factors influencing the catalytic performance. Importantly, the optimal formaldehyde removal efficiency (95.01%) and CO2 selectivity (86.20%) were acquired at 5 W discharge power, 0.5 L min(-1) gas flow rate, and 0.71 Fe/Mn molar ratio. This study can thus provide an efficient strategy for formaldehyde removal.